" K. WINTERHALT! 



LEGUMES FOR SEED 249 



the failure of the soil to produce the latter crop being due, 

 doubtless, to a lack of available nitrogen. 



The Arkansas Station found as the result of five years' trial 

 with ten varieties that the best results were obtained in seasons 

 of least rainfall, as follows: 



Influence of Rainfall on Yield of Cowpeas 



In rainy seasons the plant suffered from mildew, which de- 

 creased the yield of peas, and to a less extent the yield of hay. 1 

 While cowpeas may be grown in Canada, their climatic adap- 

 tation is south of the latitude of St. Louis. They appear to re- 

 quire warmer soil and atmospheric conditions for successful ger- 

 mination and early growth, but will withstand fall frosts better 

 than field beans. Some varieties will remain green all winter 

 in portions of the Gulf states, and thus furnish winter pasture. 



308. Inoculation. Cowpea roots almost universally bear root- 

 tubercles without artificial inoculation. Under field conditions, 

 the Alabama Station found no increase from inoculation, since 

 the roots developed an abundance of root-tubercles without 

 inoculation. 2 The New Jersey Station, however, found that 

 the first season there were few root-tubercles, but that they 

 increased each season for three years when they were abundant. 

 The growth of forage increased with the increase in the abun- 

 dance of root-tubercles. 2 



1 Arkansas Sta. Bui. No. 77 (1902), p. 32. 



2 Alabama Sta Bui. No. 87 (1897), p. 480. 



3 New Jersey Sta. Rpt. (1899), p. 200, 



